The harmonica is a popular handheld musical instrument that appeals to a wide range of players from children to seniors, amateurs to professionals. Also called a harp, French harp, blues harp or mouth organ, the harmonica is a free reed wind instrument used primarily in blues and American folk music, jazz, country and rock and roll.
One popular form of the harmonica is the ten-hole diatonic harmonica, having two reeds per hole, although there are numerous variations having different numbers of holes, and reeds per hole. As shown for example in FIG. 1, the typical construction of a diatonic harmonica 1 includes a pair of reed plates 4, 5 attached to opposing faces of a comb 2 defining an air chamber 3 there between. Each reed plate 4, 5 contains a set of flexible elastic reeds 7, 10 each affixed below rectangular slots 6, 9 through which the metallic reeds 7, 10 vibrate. The means of attachment of the elastic reeds 7, 10 to the reed plate 4, 5 may be a rivet, screw, spot weld or any other appropriate attachment means 8. The elastic reeds may be typically made from a variety of alloys including beryllium copper, phosphor bronze, brass, or stainless steel, although they may also be made from polymeric materials.
Harmonicas produce musical tones by a player blowing air into, or drawing air from, a mouthpiece containing multiple holes (or reed chambers) in a manner that causes one or more of the reeds 7, 10 therein to vibrate. The reeds 7, 10 of each reed chamber are configured such that one reed 7 is preferably played when blowing and the other reed 10 when drawing. Surrounding the reeds 7, 10 is an enclosure typically comprised of a pair of cover plates 11, 12 fashioned from metal, plastic, or wood, and providing an opening 15 to the atmosphere, usually positioned on the face of the harmonica opposite the player's mouth, downwind of the air flow.
In a non-limiting example of the operation of the harmonica, the player blows into the air chamber 3 causing the blow reed 7 to close, obstructing the reed slot 6, thereby interrupting the flow of air 14. This flow interruption causes intermittent compression and rarefaction of the air, creating acoustic sound that exits the opening 15 provided by the cover plates 11, 12 which transmit an acoustic pressure to the surrounding air, whereupon it may be perceived by the ear of a person within proximity to the instrument.
When practicing or playing for personal pleasure, however, it may be desirable to prevent the sound from being perceived by persons other than the player so as not to disturb others or to bring unwanted attention to the player.
Further, it may be undesirable or disadvantageous for the player to simply play less forcefully, as a certain minimum air flow is necessary for the instrument to operate property.
A need exists, therefore, for a way to attenuate the loudness of a harmonica so as to permit playing or practicing the instrument without disturbing others.